Gynaecological endocrinology: route of oestrogen in HRT: practice question

A OBG question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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OBG · Gynaecological endocrinology: route of oestrogen in HRT

Sample item

Why is transdermal oestradiol associated with a lower risk of venous thromboembolism than oral oestrogen in menopausal hormone therapy?

AIt does not stimulate the endometrium, so no progestogen is neededBIt is converted to oestriol, which is not thrombogenicCIt avoids first-pass hepatic metabolism, so clotting factor synthesis is not raisedDIt blocks oestrogen receptors in the liver

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. It avoids first-pass hepatic metabolism, so clotting factor synthesis is not raised

Oral oestrogen passes through the liver first and increases synthesis of clotting factors, which raises thrombotic risk. Transdermal oestradiol enters the circulation directly and has little hepatic effect. A woman with a uterus still needs a progestogen with any oestrogen to protect the endometrium.

Option by option

A. It does not stimulate the endometrium, so no progestogen is needed
The endometrium is still stimulated, and a progestogen is needed if the uterus is present.
B. It is converted to oestriol, which is not thrombogenic
Transdermal oestradiol is not converted to oestriol in a way that explains the lower risk.
C. It avoids first-pass hepatic metabolism, so clotting factor synthesis is not raised (correct)
Correct. Bypassing the liver avoids the rise in clotting factors.
D. It blocks oestrogen receptors in the liver
Oestradiol is an agonist and does not block hepatic receptors.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this OBG question

What is the answer to this OBG question?

The best answer is C, It avoids first-pass hepatic metabolism, so clotting factor synthesis is not raised. Oral oestrogen passes through the liver first and increases synthesis of clotting factors, which raises thrombotic risk.

Why is "It does not stimulate the endometrium, so no progestogen is needed" not the answer?

The endometrium is still stimulated, and a progestogen is needed if the uterus is present.

Why is "It is converted to oestriol, which is not thrombogenic" not the answer?

Transdermal oestradiol is not converted to oestriol in a way that explains the lower risk.

Why is "It blocks oestrogen receptors in the liver" not the answer?

Oestradiol is an agonist and does not block hepatic receptors.

What concept does this question test?

It tests Gynaecological endocrinology: route of oestrogen in HRT in OBG. Transdermal oestradiol enters the circulation directly and has little hepatic effect. A woman with a uterus still needs a progestogen with any oestrogen to protect the endometrium.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Gynaecological endocrinology: route of oestrogen in HRT?

Learn management algorithms as steps: PPH, eclampsia, ectopic pregnancy. Then use the flashcards and the other OBG questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.